Mass Airflow Sensors

What Are the Symptoms of a Bad Mass Airflow Sensors ?

In order to obtain the best concentration of mixture under various operating conditions, the amount of air sucked into the engine at each moment must be measured correctly as the main basis for ECU to control fuel injection. These are fault symptoms in the following for MAF Sensor.

• Poor Engine Acceleration

Poor Engine Acceleration. When the deviation of the output signal of the mass air flow sensor is not enough for the ECU to record the fault code, as the air flow signal can not accurately reflect the actual air intake, the fuel injection amount controlled by the ECU is too small, so the engine speed does not rise but falls.

• Cause 

For EFI engine with hot film mass air flow sensor, ECU judges the amount of intake air and determines the amount of fuel injection according to the current flowing through the hot film resistance, so as to meet the needs of different working conditions of the engine. If dust accumulates on the hot film to form a thermal insulation layer, once the air inlet becomes larger, the temperature change slows down, the required current becomes smaller, and the fuel injection quantity determined by ECU will be reduced. At this time, the actual air intake is relatively large, resulting in too thin mixture, which eventually leads to engine idling jitter and "tempering" during rapid acceleration.

• The Automatic Transmission Will Not Upshift to Overdrive

The automatic transmission cannot be raised to the overdrive gear. If the mass air flow sensor is short circuited to the ground, the mixture will be too thin, which will reduce the output power of the engine, and the automatic transmission will not be able to rise to the overdrive gear.